Tow forwarding apparatus



P 7, 1965 c. A. AMOS 3,204,295

TOW FORWARDING APPARATUS Filed May 27, 1965 FIG.

INVENTOR CHARLES A. AMOS BY M446 4% ATTORNEY United States Patent 3,204,295 TOW FORWARDING APPARATUS Charles A. Amos, Waynesboro, Va., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed May 27, 1963, Ser. No. 283,496 1 'Claim. (CI. 19-65) This invention relates to apparatus and process for forwarding filamentary tow.

The importance of continuous filamentary tow as an alternative to cut staple in textile processing of synthetic fibers is well established. Fewer processing steps are involved in the conversion of tow to yarns than in the conversion of staple to yarns. This provides a substantial economic stake in the tow route. Furthermore, retention of continuous filament nature of synthetic fibers in the product offered to the textile trade provides great additional flexibility in choice of treatments not feasible with the product out to staple.

In most cases the special tow treatments and economical conversion of tow to high quality yarns depend on a tow of very uniform mechanical quality. It must be a contiguous entity laterally so that it can be compressed and expanded in width to fit the processing equipment without significant loss of filament distribution uniformity along the width. Such contiguity of structure depends, among other things, on careful packaging of the finished tow for shipment. The rather bulky tow must be compressed into high density cartons for economical shipment. One of the major problems encountered in packaging derives from the sensitive dependence of tow width on tension applied and compression employed between rolls used to forward it through manufacturing process steps. This is especially true when the tow has been dried. Large variations in width resulting from small variations in processing tension and compressive force lead to entanglements among adjacent folds in the cartons and subsequent damage to the structure as it is withdrawn for textile processing.

It is an object of this invention to provide apparatus and process for improved control of finished tow width. It is a further object to provide apparatus and process to compensate, by adjustment in lateral compression, for variations in width resulting from small differences in longitudinal tension. Other objects will appear hereinafter.

These and other objects are accomplished in this invention by the use of a double-acting pneumatic or hydraulic cylinder to close the tow-advancing pull rolls, which cylinder is supplied both a closing pressure and a biasing pressure adjustable to the requirements of the individual production line. Thus, minor variations in tension normally leading to variations in width of the product tow from one production line to another are compensated for. The width of tow from all lines can simultaneously be adjusted to the desired value by a change in closing pressure alone.

The invention will readily be understood from the description, taken with the drawings in which FIGURE 1 is a vertical schematic view of the arrangement of apparatus according to this invention for one production line, while FIG. 2 is a schematic horizontal view of the arrangement of cylinders and valve connections as applied to four parallel production lines.

With reference to FIG. 1 of the drawings, tow is withdrawn from a loosely-arranged bed 11 on a continuous, perforated belt drier 12, by a pair of pull rolls comprising driver 8 and idler 9, through a system of guides schematically represented by loop guide 13 and parabolic guides 14. The guides are arranged to permit removal of folds and twists in the tow and to shape it to approximately the desired width, while maintaining good filament distribution uniformity. Normally, minor differences in tow paths which are required to direct the tow from the various locations on the drier bed to the several packaging stations result in a non-uniform tension requirement station-to-station. This results in variations in relaxed tow width, or width of the tow as it is dropped into the carton, and normally these variations are compensated for by adjustment of the closing force applied to idler roll 9. After leaving the pull rolls, tow 10 drops from piddler spout 15 into carton 16. Piddler spout 15 is driven by means (not shown) to distribute the tow uniformly over the cross sectional area of tow carton 16.

Now, according to this invention, said closing force upon each of the idlers 9 in a bank of adjacent production lines is applied by the piston 6 of a double-acting cylinder 1, which is supplied with fluid under uniform pressure established in line 2 by reducing valve 3 (FIG. 2). A lower, biasing fluid pressure is individually applied to the opposing chamber in each cylinder by individually setting reducing valves 4. All reducing valves are fed by a common pressure line 5. The higher pressure below pistons 6 tends to retract shafts 7, closing idler 9 against driver 8 with a net force empirically established as optimum for the specific production line. Driver 8 is driven by means (not shown) to forward tow 10. The widths of tows from all production lines are adjusted to equal by individual adjustments of the biasing pressures from reducing valves 4 for some given higher pressure in line 2. Subsequent adjustments in tow widths in all lines can be made by adjustment of reducing valve 3 without individual adjustments of reducing valves 4. In general, wider tows are obtained by increasing the pressure in line 2.

Tests to establish versatility of this apparatus and process have demonstrated that widths of from 6 inches to 10 inches can be obtained with the same 470,000 denier tow by varying the closing force applied via line 2. Objectionable variations in tow width from production line to production line are essentially eliminated by the process and apparatus of this invention with attendant improvement in packaged tow quality, textile processibility, and ultimate yarn quality.

It will be obvious to one skilled in the art that many variations can be made in the apparatus and process of this invention without departing from the spirit and scope thereof, and the invention is to be limited only by the following claim.

I claim as my invention:

An apparatus for forwarding tow in a plant for producing textile yarn from filamentary tow, said apparatus comprising (1) a bank of driver rolls and idler rolls mounted on parallel axes and spaced in correspondence to form a plurality of paired off driver and idler teams with a nip between each pair adapted to receive and compress a bundle of tow whereby to impart motion thereto by the rotation of said rolls, and

(2) means for regulating the pressure upon each of said tow bundles collectively and individually whereby to control the amount of lateral spread of each bundle during compression, said means including (a) a double acting fluid driven piston for each pair of rolls, each piston moving inside a pressure cylinder and being mechanically connected to the axis of the corresponding idler roll,

(b) means for supplying simultaneously fluid pressure of the same magnitude against all the pistons in the bank of cylinders, said pressure in each cylinder being directed against that face of the piston which will cause the latter to move 3 in the direction of tightening the pressure on the tow as it passes said nip,

(c) means for applying a lesser pressure to the other face of each piston whereby to offset part of the driving pressure on said first face thereby facilitating control thereof,

(d) valve means for regulating the value of said lesser pressure individually for each of said pistons, and

(e) valve means for regulating collectively the pressure applied to all of said first, mentioned faces of the pistons.

References Cited by the Examiner UNITED STATES PATENTS 2,823,535 2/58 Warner 100-170 X 2,900,951 8/59 Kabelitz 100-170 X 3,143,772 8/64 Whitehurst 19-272 FOREIGN PATENTS- 918,676 9/ 54- Germany.

10 DONALD W. PARKER, Primary Examiner. 

